Flexible intramedullary nails are used to stabilize long bone fractures in pediatric patients. They are mostly used in forearm fractures (radius and ulna) as well as humerus, femur, and tibia fractures when casting is not appropriate. The nails work well when the fracture is at the diaphysis (the middle of the bone where the medullary canal is the narrowest—see FIG. 2A) because the tight fit between the nail and the medullary canal promote stability between the two, resulting in stability of the fracture at the diaphysis. Because the nails are inserted through a small incision, they allow minimally invasive surgical treatment of fractures.
However, there are long bone fractures for which the use of flexible intramedullary nails is challenging. For example, when the fracture is at the proximal metaphysis where the medullary canal is wider (see FIG. 2B), creating a tight fit between the nails and the medullary canal at the fracture site is difficult. Without the tight fit, there is no control over the proximal fragment, allowing the proximal fragment to displace (see FIG. 2C).
Therefore, what is needed is fracture fixation devices and methods in which improved stabilization of a bone fragment to an intramedullary nail can be achieved.